US2500162A - Method of preparing viscous oils by the thermal condensation of short chain monoolkfins with long chain monoolefins - Google Patents

Description

hams Mar. 14, 1950 METHOD 2.5.0.162 PREPARING VISCOUB OILS BY THE THERMAL CONDENSATION OI SHORT CHAIN MOfiOOLEI'INS WITH LONG CHAIN MONOOLEFINS I'ranoieM.8eger,Pitman,andAlexsnderN.

Saclnnen, Woodbnry,N. 1., assignors to Sooony-Vaomnn Oil Company, corporation of New York Application September 2, 1948, Serial No. 47,556

No Drawing.

Incorporated, a

11 claim; (01. 2M1) This invention has to do with a new and novel clam of synthetic lubricants and with a method for preparing the same. More particularly, the invention has to do with synthetic lubricants characterized by an especially desirable combina-. tion of properties, namely, low pour point, high viscosity index and excellent stability.

As is well-known in the art, considerable attention has been given tothedevelopment of synthetic lubricants from various sources, particularly oleilnic hydrocarbons. For example, oleilns have been polymerized in the presence of numerous catalysts, notably those of the Friedel- Crafts type, whereupon viscous oils have been formed. In the absence of catalysts, however, oleiins as a class have not been so successfully converted to viscous oils. Ethylene has been found to be unlike most low molecular weight oleiins, in that it may be converted under high pressure and at elevated temperatures of the order of 500-750 F., in the absence of active catalysts, to high viscosity index lubricants. Other low molecular weight olefins such as propylene and butenes, which are normally gaseous in character, do not produce lubricating oils on thermal (non-catalytic) treatment. Oils obtained from propylene, butenes and pentenes, in the absence of active catalysts, are formed in only low yields and have undesirable properties, in particular, low viscosity indices. Longer chain olefins-other than normal, alpha mono-olefins having six or more carbon atoms-have also failed to form desirable viscous oils. in appreciable quantities when thermally polymerized and condensed. Typical of such olefins are pentene-2, octane-2 and 2-ethyl hexene-l. With still longer chain olefins such as those having about twenty or more carbon atoms, substantial yields of synthetic oils of high viscosity indices have been realized; yet, such oils have excessively high pour points.

' In application Serial No. 761,716, filed July 19,

chain length falls within the range of six to twelve carbon atoms. Thus, the present invention makes possible for the first time the use of inexpensive short chain mono-oleflns for the production of synthetic lubricants, by thermal means. In this way, then, readily available commercial materials may be used, thereby lowering the cost of raw materials and hence the ultimate cost of the product. For economically practical operation on a commercial basis, mixed olefinic materials of relatively long chain length such as those obtained from cracked hydrocarbon waxes or cracked parafllnic distillates, and from Fischer- Tropsch and related processes, constitute desirable sources ofraw materials.

Reactants The short chain mono-olefin reactant used herein is one having from 2 to 6 carbon atoms 1947 by applicants and now abandoned, and of ,which this application is a continuation-in-part, disclosure was made of the discovery that normal,

alpha mono-olefins having from six to twelve carbon atoms can be converted by thermal, nonper molecule. Typical of such oleflns are ethylene, propylene, butene-l, butane-2, isobutylene, pentene-l, pentene-2, hexane-1, hexene-2, hexane-3, etc. Inasmuch as the normal, alpha mono-oleiins of this group form outstanding synthetic lubricants with the long chain normal, alpha monooleflns (defined below), they represent preferred short chain mono-oleilns. It will be understood,

of course, that individual mono-olefins of the foregoing group maybe used, and that mixtures of two or more of such short chain mono-oleflns may be used.

As indicated above, the other mono-olefins used in forming the synthetic lubricants of this invention are long chain normal, alpha mono-olefins containing from 10 to 30 carbon atoms per molecule. In some instances, the mono-olefin may contain as many as 30 carbon atoms per molecule. Preference is given, however, to those falling within the range of 12 to 20 carbon atoms per molecule, such preference being based upon the outstanding lubricants obtained therefrom in association with the foregoing short chain monooleflns. Illustrative of long chain normal, alpha mono-oleflns are the following: decene-l, und cene-l. dodecene-l, octadecene-l and the like. It will be clear from the foregoing examples that an alpha olefin may also be referred to as a 1- olefin.

Not only may the long chain mono-oleflns of the aforesaid character be used individually in tures are those containing a major proportion of a l-olefln or l-olefins. In general, such mixtures should preferably contain not more than about 20% by weight of hydrocarbons other than straight chain l-oleflns of the type described. In

In many instances, in commercial operation, it

will belfound desirable to use technical grades of l-olefins. Mixed olefinic materials derived from thermal cracking of hydrocarbon wax or from the l'ischer-Trop'sch process constitute satisfactory charging stocks, with the short-chain ,olefins. In this connection, it must be noted that it is suspected that substantiallygstraight chain l-oleilns, i. e.,1-olefins" which thelength of. the side chain or chainsis s rt relative to'the length of the main chain, are also suitable, although less advantageous charge stocks fonth'e purpose of the present invention. In view of the unavail- .ability of such olefins, however,- no test data can be adduced toconfirm suspicion I The most conditions, coupled '4 (1) The volatile, non-oily component of the reaction mixture become progressively more saturated,asindicatedbyadecreaseinbromineaddition number and, therefore, less suitdile for recycling for further conversion;

(2) Crackingbeginnasevidencedbygaspressure and decrease in oil yields: and

i3) Cyclization begins, as evidenced by some decline in viscodty index with accompanying increase in gravity and refractive index.

In connection with the foregoing side reactima and secondary reactions, it should be noted that all present data indicate thata true interpolymer .of'the olefin reactants is formed. Altholuh the reaction mechanism involved is not completely understood, and it late be'understood that the invention is not to be restricted to any reaction mechanism, it does not appear thatthe excellent results obtained are attributableto separate D01!- merization'of the short chain mono oleiln and of. the long chain l-olefin. It is most probable that wax-like material wouldbe formed by a separate polymerization of long chain l-olefin and the presence of such material would be indicated by-a high pour point of the product- Inasmuch as the products have relatively. low pour points, it is unlikely that any appreciable individual polymerization of the long chain l-oleiln occurs under the conditions of operation; Similarly, should any substantial portion of ,thejshort chain olefin poly- 80 v i y with the specific character of the aforesaid re mam separately the PM woman the,

- actants, are the proportion of the reactants and '-the temperature of reaction. I I

' As indicated previously, the short chain monoolefin having from 2 to 6 carbon atoms and the when It is on this basis than. thtithgwom long chain normal, alpha mono-oleilnare reacted in such molar proportions that the mean value of the olefin chain length in the-reaction mixture is from about 6 to about 12 carbon atoms. In other words, one molar proportion Methylene, 2 carbon atoms, may be suitably reacted with one molar proportion of hexadecene-l, 16 carbon atoms, for the mean value of he ole nlength of theoriginal reaction mixture'is then nine carbon atoms. Similarly, one molar proportion'ofisobutylene, four carbqnp oms. andone .4; .lnqhsr preferredcontemplated herein; in this the mean value is eleven carbon atoms. By way of further il lustration, two molar proportions of propylene, 3

carbon atoms, and one molar proportion of tetradecene-l, 14 carbon atoms, form asuitablereaction mixture, witha mean value-of 6.7. Partlculariy outstanding synthetic lubricants are formed when the mean value of the original "reaction mixture is about 10.

With regard to reaction temperature, it has been found that this factor should be maintained within the range of from about 500 F. to about cause the products have 'high pour points, and

750 1''. Most satisfactory results, however, are obtained when operating within the more limited range between about 600 F. and about 700 F. Operation under the latter conditions makes, possible synthetic lubricants of outstanding quality, in satisfactory, commercially feasible yields.

At temperatures between about 500 F. and 600 F., conversion of the olefin reactants to synthetic lubricants takes place at a slower rateand is usually less complete. Attemperature's greater than 700 F., side reactions and secondary reactions begin to occur, and increase in importance to such an extent that at temperatures above about 750 l"., the process becomes impracticable. These side reactions'and secondary re actionsarechiefiythefollowins:

low viscosity indices. 'As empb'asisedabove, however, the synthetic lubricanh of1this invention have high viscosity indices, 01' the 0rde'nofl00 and jucts are considered to be true interpolymers. Other reaction conditions to be considered in forming the lubricants contemplated herein are pressure and reaction time. The pressure to be 40 used is not particularly critical. It may range -from about 100 to about 10,000 pounds per square "inchfofiven hi'gher. Increased pressure is desirable and, as expected, increased oil'yields result. Pressures greater than about 500 per square Reaction time varies inversely with temperature. Satisfactory products and satisfactory yields of the same have been obtained with reaction times as short'as one hour or less and as so long is thirty hour-s1, Preferably, the time is in f the neighborhood of five to ten hours, at about 600' 1'. Most advantageous results are realized with,a reactl'on'time of from three to twenty hours at temperatm-es from about 600 1'. to about 55 .650 1''. Test data also indicate that reasonable yields of products of comparatively high viscosity index may be obtained at temperatures of 760. l'. ,to 800 F. with times of several minutes. These conditions are not advantageous, however, be-

66 viscosity index decreases sharply with prolonged exposure to these higher temperatures, namely, 750-800 F.

w Examples 10 In order to muse -me principles of this invention, the results of a series of typical, and non-limiting, condensations are set forth in tabular form in Table I below. These condensations were carried out in a roofing-type bomb (American Instrument (10.). In the case of hexa- Run No; 8 9

8 decene-i and ethylene, for example, the bomb wasoharged with 224 parts by weight (1 molar proportion) of hexadecene-l. The atmosphere in the bomb was replaced with nitrogen and the bomb was then evacuated. Ethylene was next admitted from a cylinder. The bomb was then heated to the desired temperature for the desired length of time. During the run, ethylene was added several times. The total pressure drop was noted. The bomb was cooled and discharged.

, The contents of the bomb were vacuum topped to remove the more volatile non-viscous materiais, and the product was filtered. To distinguish the condensation products from the distillate products thereof, the refined oils are identified as "residual oils. The latter term identifies the oils from which unreacted materials and products of intermedtate boiling range have been separated. j

It should be noted that the reaction times, recited in "Time, Hours" in Table I, represent the time intervals during which the bomb was maintained'at the desired temperature; and do not include the time intervals necessary. to heat the 10 ual oils in Table I were subjected are well known standard tests. In this connection, it will be noted that the designation 'N. N. refers to "the neutralization number, which is a measure of the acidity of the oil; the designation Br: No." refers 15 to the bromine addition number, which is a measure of the unsaturation of the oil; the designation Carbon Res." identifies the carbon residue,

Ramsbottom determination; the .designation Vis., S. U. S. 210 F.refers to the viscosity at 210 F., in'Saybolt Universal seconds as converted from kinematic determination; the abbreviation V. I. represents viscosity index; "Means C chain" refers to the mean carbon chain length of the olefins charged.

Table I Run No l 2 Ethylene; 35A

Ethylene... 34 1.25.. 1. Deane-1....

Long Chain 0 efln..

Parts by Weizht Molar Proportions.

Temperature, F. Time, Hours. Atmos here Max. ressure, p. s. i Cumulative Pressure Drop, p. s. i. g. Vacuum Distillate:

Parts by Weight Yield, per cent Spec. Gravity Parts by Weight Yield, per cent Spec. Gravity.-.. Bl: N0 N. N Refractive Index Carbon Rea, Wt. per cent. Vis., S. U. S. 210 F V. I.; Pour Point, F

Ethylene Pro lene. 67 102.

Short Chain Olefin Temperature, F. Time, Hours..... Atmosphere Max. Pressure, p. s. 1 Cumulative Pressure Drop, p. 5.1. g Vacuum Distillate:

Parts by Weight Yield, r cent 650.. 10 Evacuated. B25

Octane-2.

V. I Pour Point.

Nous-See footnotes on following page.

- hexadecene-l.

. Table I Bill N0": 15 1Q 11 ll 19 a Short Chain Oleiin..' A Isobuten Isobuten Henna- Parts b; Weigh 228 I! 84 Molar ingenious"... 4.1. 8.1.. 1.0..

lm chain 0 tin Hexadeoene-l- Handsome-1 arts b Weigh m Molar roportiom 1 0 1 n 0 Oieiins. Mixed Oleiins... Feature-2. C.-Poiymar...- Mind Olaflm.

Para. 1, Wei ht no 112 m Molar mportinnl 0.13 no Mean 0 Chain- 6.8. L4 6 i1 0 CL 8.

Temperature, '1... 650 650 616 can on ma Evacuated Evacuated N," N, a. Max. ,p.s.i.- 4 35m 1728 Jill M. 400. Cumulative Pressure Drop, p. a. i. g. 4126 850' 100 lm 60. Vacuum Distillate:

Parts by Weight 17B 200 101 46. Yield, r an 30.3.- 61.2.- 82.8. 14- Spec. ravity 0. 0.6478. 0.7857" 0.76. Bn No 40.1- 43.9. 67.7-. .7.

Residual Oil:

' Parts by Weight 192 I .148 I 68. Yield, I cant 42.5- 12.6.. 2.5.. 46.4.. 1.74.- I4. Spec. ravity 0.858.- 0. 0.7778--.-- 0.8270. 0.8. Bn No 18.4. 88.8 2i.6--.' 77.4. N. N.- l 2 0.2.. 0.1. Refractive Index..

Carbon Rea, Wt. per cent 0.02. 1.1..--

Via, B. U. 8. 0 210 F 42.41 73- 3 38.77 ALI.

V. I 132 138.0 187.3. Pour Point, '1' 10 -1 -l5 m.

Ethylene reacting. calculated from weight oi liquid product in bomb.

I Mixed oieiins; boiling range 570-0 c Mixed oieiins; iling range 44-22.? 0.; avenge carbo D At approximately I At approximatel charge of oleiins shown.

I Approximately 30 sec. 6. U. G 100 1 Considering only 30 g. oleflns oi Cu 1 V. I. oii-scale-cann I From the data set forth in Table I above, several observations may be made. Run 1 indicates .that a synthetic oil of excellent quality may be standing viscous oils, the oleflns being so proportioned on a molar basis that the mean carbon chain length ranges from 6.1 to 7.4. Each of the oils formed in Runs 2, 3 and 5 is characterized by a V. I. substantially above 100. Run 4 shows an oil'obtained by thermal conversion of decene-l, such an oil being shown for purposes of compari son with the oils of Runs 2 and 3; Run 4 is typical of those described in the aforesaid parent application. Run 5 shows an excellent oil of this invention, the 011 being derived from ethylene and In comparison, the oil obtained from hexadecene-l alone, in Run 6, has a most satisfactory viscosity index but an excessively high pour point.

Demonstrating that thermal conversion of short chain olefins alone results in low yields of V viscous products of poor quality are Runs '7, 8, 9 and '10. For example, the yields range from 2.8% to 8.5%, and the viscosity indices range from 85 to 35.8. Run 11 illustrates an oil having a V. I. of only 84; the mean carbon chain length 20 It; Bn No-10; average carbon chain about 16; obtained from cracking of bee I oll. Low bromine number indicetgg only about 16 per cent oleiins, remaingfilgemiiins.

about 8; obtained from thermally cracked paraflin was.

mixtureoinoueneaiowinalpbaokiineontent.

range. 0!: be calculated significantly ior very low viscosity produ t,

Run 17 shows the unsatisfactory oil obtained in low yield from pentene 2 which, of course, is

not an alpha olefin.

Run 18 shows anexcellent oil obtained from a mixture of hexene-l and hexadecene-i in proper proportion.

Run -19 involves thermal conversion of mixed nonenes, low inalpha olefin content, with the formation of only a small'quantity of residual oil; such is not contemplated herein.

Run 20 is also illustrative of the oils of the aforesaid parent application.

As will be evident from the data presented above in Table I, the condensation products of this invention are highly desirable lubricants per se. They are about considerable value as blending agents for other lubricating oils. In view of the inherent stability of the synthetic oils, they impart stability to the oils with which they are blended. So also, they impart desirable viscosity index (V. I.) and pour point characteristics to the oils in combination therewith, for, as indicated' above, the have advantageous viscosity index and pour point properties. In short, the syntheticoils find utility in "upgrading other lubricants. Typical oils with which the synthetic oils may be blended are mineral oils such as are normally used in internal combustion and turbine engines. When so blended, the synthetic oils may comprise the major proportion of the final blended oil, or may even comprise a minor procarboxylate of a gnome:

said short chain and long chain olefins being reacted in such molar proportions that the mean value of the olefin chain length in the olefin mixpressure agents are well (known; illustrating such materials are numerous chlorine and/or sulfur containing compositions, one such material being a chlornaphtha xanthate. Silicones, such as dimethyl silicone, may be used to illustrate foam suppressing compositions. Viscosity index improving agents which may be used are typified by polypropylenes, polyisobutylenes, polyacrylate esters, and the like.

contemplated also as within the scope of this invention is a method of lubricating relatively moving surfaces by maintaining therebetween a film consisting of any of the aforesaid oils.

It is to be understood that the foregoing description and representative examples are nonlimiting 'and serve to illustrate the invention,

which is to be broadly construed in the light oithe language of the appended claims.

We claim:

l. The method for preparing a viscous oil, which comprises': thermally and non-catalytically condensing, at a temperature between about 500 F. and about 750 F. for a period of time from about twenty hours to about one hour, respectively, an olefin mixture consisting essentially of a short chain mono-olefin having from two to six carbon atoms per molecule and a long-chain normal, alpha mono-olefin having from ten to thirty carbon atoms per molecule; said short chain and long chain olefins being reacted in such molar proportions that the mean value of the olefin chain length in the olefin mixture is from about six to about twelve carbon atoms.

. 2. The method for preparing a viscous oil, which comprises: thermally and non-catalytically condensing, at a temperature between about 600 F. and about 700 F. for a period of time from about five to about ten hours at 600 F. to about one hour at 700 F., respectively, an olefin mixture consisting essentially of a short chain mono-olefin having from two to six carbon atoms per molecule and a long chain normal, alpha monoolefin having from ten to thirty carbon atoms per molecule; said short chain and long chain olefins being re-- acted in such molar proportions that the mean value of the olefin chain length in the olefin mixture is from about six to about twelve carbon atoms.

ture is from about six to about twelve carbon atoms.

5. A viscous oil characterized by a viscosity index of at least about 100 and by a low pour point, and obtained by: thermally and non-catalytically condensing, at a temperature between about 500 F. and about 750 F. for a period of time from about twenty hours to about one hour,

3. The method for preparing a viscous oil,

which comprises: thermally and non-catalytically condensing, at a temperature between about 500 '1". and about 750 F. for a period of time from about twenty hours to about one hour, respectively, an olefin mixture consisting essentially of a short chain mono-olefin having from two to six carbon atoms per molecule and a long chain normal, alpha mono-olefin having from twelve to twenty carbon atoms per molecule; said short chain and long chain olefins being reactedin suchrespectively, an olefin mixture consisting essentially of a short chain mono-olefin. having from two to six carbon atoms per molecule and a long chain normal, alpha mono-olefin having from ten to thirty carbon atoms per molecule; said short chain and long chain olefins being reacted in such molar proportions that the mean value of the olefin chain length in the olefin mixture is from about six to about twelve carbon atoms.

6. A viscous oil characterized by a viscosity index of at least about and by a low pour point, and obtained by: thermally and non-catalytically condensing, at a temperature between'about 600 F. and about 700 F. for a period of time from about five to about ten hours at 600 F. to about one hour at 700 F.. respectively, an olefin mixture consisting essentially of a short chain monoolefin having from two to.six carbon atoms per molecule and a long chain normal, alpha monoolefin having from ten to thirty carbon atoms per molecule; said short chain and long chain olefins being reacted in such molar proportions that the mean value of the olefin chain length in the olefin mixture is from about six to about twelve carbon atoms.

.7. A viscous oil characterized by a viscosity index of at least about 100 and by a low pour point, and obtained by: thermally and non-catalytically condensing, at a temperature between about 500 F. and about 750 F. for a period of time from about twenty hours to about one hour,

respectively, an olefin mixture consisting essentially of a short chain mono-olefin having from two to six carbon atoms per molecule and a long chain normal, alpha mono-olefin having from twelve to twenty carbon atoms per molecule; said short chain and long chain olefins being reacted in such molar proportions that the mean value of the olefin. chain length in the olefin mixture is about ten carbon atoms.

8. A viscous oil characterized by a viscosity index of at least about 100 and by a low pour point, and obtained by: thermally and non-catalytically condensing, at a temperaturebetween about 500 F. and about 750 F. for a period of time from about twenty hours to about one hour, respectively, an olefin mixture consisting essentially of a short chain normal, alpha mono-olefin having from two to six carbon atoms per molecule and along chain normal, alpha mono-olefin having from twelve to twenty carbon atoms per molecule; said short chain and long chain olefins being reacted in such molar proportions that the mean value of the olefin chain length in the olefin mixture is from about six to about twelve carbon atoms.

9. A viscous oil characterized by a viscosity index of at least about 100 .and by a low pour point, and obtained by: thermally and non-catalytically condensing, at about 660 F..for about ten hours, an olefin mixture consisting essentially of ethylene and hexadecene-l; said ethylene and hexadecene-l being reacted in such'molar proportions that the mean value of the olefin chain 11 12 lenethintheoleiinmixtureiaaboutlixearbon abouttenhom'aanolennmixtureoomietineeeatoms. sentially of hexene-l and; hexadeoene-l: ll!!! 10. A vieooue oil characterized by a vieooeity hexene-l and hexadeeene-i beinzreaeted in such index of at least about 100 and by a low pour molar proportion; that the mean value of the point, and obtained by: thermally and'non-oataolefin chain lenzthin the olefin mixture is a lyttoally condensing, at about 650' 1". for about eleven'carbon atoms.

tenhouraanoleflnmixturoooneistin: eesen- FRANCISILBIGER. Q tially o! isobutene and hexadecene-l; said iso- ALEXANDER N. SACHANIN. butene and hexadecene-ilbeinz reacted in such molar proportions thatthe mean value of the 10 Bmcls CITED olefin chain lenzth in the oleflnmlltm'e 18 W. The following reference: are of record inthe naw ncnmnmby viscosity meofmspmn U8 0 g l index ot'at least about 100 and by a low pour m STAT PATENTS point, and obtained by: thermally and non- II Number flame pm eatalytically oondenlinz. at about. 860' I. tor 2,315,080 Reid.....--...--....llar.30,1948

Claims (1)

1. THE METHOD FOR PREPARING A VISCOUS OIL, WHICH COMPRISES: THERMALLY AND NON-CATALYTICALLY CONDENSING, AT A TEMPERATURE BETWEEN ABOUT 500*F. AND ABOUT 750*F. FOR A PERIOD OF TIME FROM ABOUT TWENTY HOURS TO ABOUT ONE HOUR, RESPECTIVELY, AN OLEFIN MIXTURE CONSISTING ESSENTIALLY OF A SHORT CHAIN MONO-OLEFIN HAVING FROM TWO TO SIX CARBON ATOMS PER MOLECULE AND A LONG-CHAIN NORMAL, ALPHA MONO-OLEFIN HAVING FROM TEN TO THIRTY CARBON ATOMS PER MOLECULE; SAID SHORT CHAIN AND LONG CHAIN OLEFINS BEING REACTED IN SUCH MOLAR PROPORTIONS THAT THE MEANS VALUE OF THE OLEFIN CHAIN LENGTH IN THE OLEFIN MIXTURE IS FROM ABOUT SIX TO ABOUT TWELVE CARBON ATOMS.